The orca slicer brim object gap is the space between the innermost brim line and the part. Enlarging it makes the brim easier to peel away, because less of the brim is attached to the model — the adhesion benefit the brim adds is reduced. That is a different interface from the brim's grip on the build plate: the gap shrinks how much help the brim gives the part, not how well each brim line sticks to the plate.
What the brim object gap actually changes
In Orca Slicer, Brim-Object Gap is an Advanced setting stored as brim_object_gap. The official documentation defines it in a single sentence: it is the gap between the innermost brim line and the object. Increasing the gap makes the brim easier to remove but reduces its adhesion benefit, and a very large gap may eliminate contact with the part altogether (Orca Slicer brim settings; orcaslicer.com brim settings).
The setting moves the brim's inner edge relative to the model. It does not widen the brim, choose where the brim is printed, or set how far supports sit from the part. Those controls are separate, but not unrelated — the brim footprint, the plate, the material and the part geometry all act on the same first layer, so a gap change also changes how much brim surface can hold the part and where the removal force lands.
Gap, width, type and support clearances are four different controls
Control | What it is responsible for | What it does not do |
|---|---|---|
Brim-object gap ( | Space between the innermost brim line and the object | Does not widen or narrow the brim |
Brim width ( | Distance from the model to the outermost brim line; wider brims can hold better but use more material | Does not change the inner-edge clearance |
Brim type ( | Where the brim is generated — outer, inner, both, or mouse ears | Does not set any gap value |
Support or raft clearances | How supports or a raft sit relative to the part | Not part of the brim settings; not a substitute for the gap |
"My brim is hard to remove" has several possible causes, and the gap is only one of them.
Diagnose in the first-layer preview before you change a value
- Slice the model with the profile you actually intend to print.
- Open Preview and go to the first layer.
- Zoom into the base and check whether the innermost brim line still touches the object or already stands apart.
- Note which brim type is active, if any.
- Confirm which preset holds the setting you are about to edit, so you can undo one change later.
This step is diagnosis, not proof: a rendered preview shows geometry and does not prove that the brim will hold or come off cleanly. If the base looks swollen rather than loose, check elephant foot compensation — it corrects the same first layers from a different direction. Adhesion also depends on the build plate, material, first-layer squish, part geometry, and your Orca Slicer profile.
Change one setting and record what happens
Run a small, separate trial instead of reprinting the real part. Keep material, plate, nozzle, temperatures, first-layer settings, and the rest of the profile fixed, and move only the gap. If the profile is still being tuned, work through the recommended calibration order first, so the trial measures the gap and not an uncalibrated flow. Print a small flat test piece that represents your typical base, then record what you observe:
Material and plate | Gap (mm) | Preview contact | Removal | Notes |
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No single value is universal. The documentation describes a direction, not a number: a larger gap eases removal and weakens the hold, while a very large gap can remove contact. A fixed 0.1 mm for every filament, or zero gap as a universal answer, does not hold up; the value depends on your machine and material, so your own trial decides it.
The goal is an acceptable combination for the setup you tested: the brim holds the part through the print and still peels away without a fight. Neither preview contact nor one small trial proves performance on a worst-case part, so repeat the trial on the geometry or material that troubles you most. A gap change is a bounded, one-variable test of your material, plate, and profile — not a guaranteed rescue for a failing print.
Verify after the print, not only in the slicer
After the trial prints, judge the result on the actual part: how much force the brim needed and whether the part stayed stuck. If removal is still hard, treat width, type, first-layer behaviour, and the gap as separate candidates and change one at a time. If the part lifted, the brim needs to contribute more contact — a wider brim or a different brim type are candidates, tested the same way.
Treat all of this as version-dependent: confirm current behaviour on the official documentation pages, then check it against your own Orca Slicer version, preset, plate, and material.
